Choose the correct options to complete the sentences

1. I didn't pick up the phone
   [so|because] I didn't hear it ringing.
2. I left the concert early,
   [so |because] I didn't hear Emma singing. Was she good?
3. I decided to go on foot
   [so|because] the weather was so lovely!
4. I missed the last bus,
   [so|because] I had to go on foot.
5. No one wanted to cook,
   [so|because] we ordered a takeaway.
6. I came home and went straight to bed
   [so|because] I was exhausted.
7. I didn't want to stay in that hotel
   [so|because] I'd stayed there before and didn't like it.
8. I didn't know anyone at the party,
   [so|because] I was bored.
9. All the flights were cancelled
   [so|because] of the storm.
10. They didn't get the invitation on time,
    [so|because] they didn't come to our wedding.